You can run
a Power Cleaning using a utility on your Windows or Mac computer.
Note: After
running a Power Cleaning, you must turn off the product and wait at
least 12 hours before running another Power Cleaning.
If print quality has not improved
after running Power Cleaning, wait for at least 12 hours without
printing, and then print the nozzle check pattern again. Run Print
Head Cleaning or Power Cleaning again depending on the printed
pattern. If quality still does not improve, contact Epson
support.